Year-round edamame: hydroponic LED plant factories redefine sustainable cultivation

Artificial light-type plant factories are an emerging agricultural innovation that enable crops to be grown year-round in precisely controlled environments. By adjusting factors such as light, temperature, humidity, carbon dioxide concentration, and nutrient delivery, these facilities can produce stable yields independent of climate conditions. They offer a promising way to reduce pesticide use and minimize the impacts of climate change. However, legumes like edamame have long been considered difficult to cultivate in such settings because of their long growth periods, short storage periods, complex flowering, and pod-setting processes. 

Against this backdrop, the research group, led by Professor Toshio Sano from the Faculty of Bioscience and Applied Chemistry, Hosei University, Japan, and Associate Professor Wataru Yamori of the Graduate School of Agricultural and Life Sciences,  The University of Tokyo, Japan, had previously gained attention for successfully cultivating tomatoes under LED lighting in a plant factory. Building on that success, they set out to tackle edamame, a high-protein, nutrient-rich legume widely consumed worldwide. The findings were published online in the Volume 15 of the journal Scientific Reports on September 12, 2025. 

Edamame is traditionally harvested only during the summer months, and its freshness deteriorates rapidly after harvest, making it challenging to distribute or store for long periods. To overcome these barriers, the team conducted comparative experiments using three hydroponic systems: nutrient film technique (NFT), rock wool culture (ROC), and mist culture (MIST ). Their findings revealed that NFT provided the most vigorous plant growth, producing stronger stems, healthier leaves, and greater biomass than both other hydroponic methods and traditional open-field cultivation. 

Importantly, NFT also resulted in more pods and seeds, leading to yields that surpassed those achieved in the field. This demonstrated that it is not only possible to cultivate edamame indoors, but also to achieve higher productivity than conventional farming.

“Recent global warming and extreme weather events have raised concerns about reduced yields in open-field crop production. Our hydroponics technology offers a promising model for urban agriculture that is independent of climate conditions,” says Prof. Sano.

The team conducted quality analyses of the edamame produced through different cultivation methods and found notable differences. Plants grown using NFT had higher sucrose content, giving them a stronger sugar content compared to field-grown edamame. While free amino acid levels were slightly lower, the NFT method produced significantly higher levels of isoflavones, compounds known for their health benefits. The researchers suggested that LED lighting may stimulate the synthesis of these bioactive components, enhancing nutritional value beyond what is possible in open-field cultivation. This combination of superior taste and elevated health-promoting compounds marks a meaningful advancement in food quality achieved through controlled agricultural environment.

When multiple factors such as yield, sugar content, and nutritional value were evaluated, NFT cultivation was rated the highest overall. The method is also well suited for vertical, multi-layered growing systems, making it ideal for urban environments where land is scarce. By stacking production layers, farmers can maximize output without increasing the physical footprint of their facilities. This scalability, combined with year-round production capability, offers a promising solution for feeding growing urban populations in a sustainable manner.

The implications of this achievement extend far beyond urban agriculture. “Since edamame is cultivated not in open fields but through hydroponics in an LED-based plant factory, it may become possible to grow edamame even in urban areas, deserts, or outer space,” adds Prof. Sano as a long-term implication of the study. High-protein, nutrient-dense crops like edamame could provide a vital food source for long-term space exploration missions. By breaking the long-standing assumption that legumes cannot be cultivated in artificial light-type plant factories, this research sets the stage for major advancements in food security and sustainable agricultural systems.

This world-first success demonstrates that “growing delicious edamame anytime, anywhere” is no longer just an ambitious idea but an achievable reality. It represents a significant step toward resilient and innovative food production models that can support healthy diets and address global food challenges. From city skyscrapers to deserts and even outer space, this breakthrough points to a future where sustainable agriculture is no longer bound by season or geography.

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Reference

Authors: Tomoki Takano¹ , Yu Wakabayashi¹, Soshi Wada², Toshio Sano², Saneyuki Kawabata¹ and Wataru Yamori¹

Title of original paper: Sustainable Edamame production in an artificial light plant factory with improved yield and quality

Journal: Scientific Reports

DOI: 10.1038/s41598-025-17131-w

Affiliations:
¹Graduate School of Agricultural and Life Sciences, The University of Tokyo, Nishitokyo, Tokyo, Japan
²Faculty of Biosciences, Department of Clinical Plant Science, Hosei University, Tokyo, Japan

About Professor Toshio Sano from Hosei University, Japan
Dr. Toshio Sano is a Professor at the Faculty of Life Sciences, Hosei University. His research focuses on plant nutrition and physiology, particularly the molecular mechanisms of nutrient absorption and metabolism. He aims to develop techniques for cultivating crops with enhanced nutritional value and improved food functions. He has contributed to advancements in controlled-environment agriculture, including the first stable hydroponic cultivation of edamame in artificial light plant factories. His work has been widely recognized in scientific publications and research initiatives in sustainable crop production. He has published more than 50 articles with over 2,500 citations.

About Associate Professor Wataru Yamori from the University of Tokyo, Japan
Dr. Wataru Yamori is an Associate Professor from the Graduate School of Agriculture and Life Sciences, The University of Tokyo, Japan. His major research revolves around photosynthetic systems, mechanisms during food shortages, and developing cultivation systems in plant factories. Also, he conducts research to improve productivity of crops using physiological ecology and molecular physiology techniques. He has more than 100 publications with over 7,500 citations.

About Hosei University, Japan
Hosei University is one of the leading private universities in Tokyo, Japan. It offers international courses in many disciplines and has a long and rich history. Founded as a school of Law in 1880, Hosei University evolved into a private university by 1920. The university is also home to multiple research centers that conduct advanced research in various fields, including nanotechnology, sustainability, ecology, and more. The university has three main campuses—Ichigaya, Tama, and Koganei—located across Tokyo.
For more information, please see: https://www.hosei.ac.jp/

About The University of Tokyo, Japan
The University of Tokyo was established as the first National University in Japan in 1877. The University of Tokyo conducts research across various disciplines and provides a professional setting for intellectual development, along with opportunities to develop knowledge and skills. The university has also implemented the initiative of Green Transformation to achieve virtually zero greenhouse gas emissions, by collaborating with local communities located near the campus. Furthermore, the university offers extensive support in the development of start-up companies, empowering entrepreneurship.
For more information, please see: The University of Tokyo: https://www.u-tokyo.ac.jp/en/ 
Graduate School of Agricultural and Life Sciences / Faculty of Agriculture, The University of Tokyo: https://www.a.u-tokyo.ac.jp/english/